Roll off control



July 7, 1959 s. s. ROMANO ET AL 2,893,345

ROLL OFF CONTROL Filed March 28, 1957 2 Sheets-Sheet 1 IEGZ 2 INVENTOR. Sam/5. @mana BY and? 147'! w R k y 7, 1959 s. s. ROMANO ET AL 2,893,346

ROLL OFF CONTROL Filed. March 28, 1957 2 Sheets-Sheet 2 iiHH I INVENTOR. Sam Siamano R'OLL OFF CONTROL Application March 28, 1957, Serial No. 649,243 8 Claims. (Ch lls-424.1)

This invention relates to roll-oif control-means for a pro-amplifier system or the like, and more particularly to means for obtaining exceptionally well controlled high fidelity by visual calibration of the bass and treble sounds.

Heretofore, it has been impossible to obtain an accurate indication of the relative strengths of bass and treble sound ranges, despite the fact that reproducing systems have become increasingly sensitive so that any variation from the desired strength in the bass or treble ranges creates a large amount of over-emphasis as com.- pared with that produced by previous equipment of less sensitivity.

Although means for adjusting the relative strengths of treble and bass ranges have been available for many years, manual rotation of the control knobs employed therewith has been subject to the difficulty that a given sound or sequence heard during the time adjustment was being made often provides a false impression of the relative strength of one or the other component sound, partied larly where different types of instrumental recordings are reproduced successively. The operator is not sure by listening to each recording what the normal or flat setting should be.

Accordingly it is an object of the present invention to provide a roll-oil control for a pre-amplifier system creating an extremely accurate visual representation of the relative strengths of treble and bass sound ranges.

Another object of the invention is to provide means for calibrating the treble and bass so that their relative orientation may be observed from a normal or fiat alignment, which flat alignment, as visually ascertainable, also corresponds to an actually flat or evenly balanced sound impression pattern designed into the amplifier.

Another object of the invention is to provide a roll-oil control as described wherein change between a fiat, balanced adjustment and a position emphasizing or deemphasizing treble or bass respectively is achieved smoothly and with a continuously uniform variation in balance from one position to the other permitting constant visual as well as auditory sensing of the adjustment being made.

Another object is to provide a roll-off control in which the bass and treble are separately adjustable by means of indicia aligned with individual viewing screens and visually perceptible means movable with respect thereto so that any relation can be attained or returned to for playing any particular recording.

Another object of the invention is to provide means as described wherein the relative strength between treble and bass can be judged by comparison of the respective movable representations thereof.

Another object of the invention is to provide manually rotatable means which are connected directly to potentiometer means in accordance with standard procedure, the manually rotatable means having pulley means secured thereto for actuating the visually perceptible means from one position to another.

Another object of the invention is to provide a roll- United States Patent D off control as described wherein the visually perceptible a 2,893,346 V iPatent ed July 7, 1959 means include a pair of relatively wide screens of suit- 'sitions with respect to cooperating indicia on the screens.

Another object of the invention is to provide a roll-off control as described wherein volume may also be determined visually in relation thereto by means 'of a screen preferably central of the previously described screens and a substantially horizontal shaft, the inner ends of said pair of-sh afts being movable vertically independently relative thereto. 1 I v Other objects and advantages of the-invention will become apparent as the description proceeds in accordance with thedrawings in which: v v

Fig. 1 is a front elevational view of a roll-off control means in accordance with the present invention; 7

Fig. 2 is a top plan view of the control means of Fig.

Fig. 3 is a side elevation'al'view of the control means;

Fig. 4 is a vertical sectional view taken along the lines 4-4 of Fig. 3; t

Fig. 5 is a fragmentary view of manually rotatable control means such as shown on Fig. 4;

Fig. 6 is an enlarged, broken vertical sectional view of pulley, means in accordance with the invention; and

Fig. 7 is an enlarged vertical sectional view corresponding to the view of Fig. 5. r

Referring now to Fig. 1, a roll-01f controlsystem 10 is shown in use with a pre amplifier system 12, as seen in Fig. 2, and has a plurality of manually rotatable control knobs 14, 16 and '18 for controlling bass, volume and treble, respectively of an audio amplifying system. The control system 10 provides a panel 20 (Fig. 1) defining a pair of substantially rectangular color contrast screens 22 and 24, having log-graph lines thereon indicating frequency (horizontal lines 20f) and decibels (vertical lines 20d) as well as a central, preferably relatively narrow panel section 26,- it being appreciated that the dimensions and construction of these screens are for purposes of illustration only.

In order to provide visual indication of the relative position or strength of treble and bass, a pair of flexible wands, rods or shafts 28 and 30 are disposed across each of the screens 22 and 24, respectively, and secured as at 3'2 and 34 to the control panel by means of suitable brackets 36 and 38. The "shafts 28 and 30 may be of suitably flexible material, such as reed or colored wire or plastic, and have the outer ends thereof received'in brackets 40 and 42 aflixed to individual pulley ropes 44 and '46. The brackets 40 and 42 are fixedly secured upon the said ropes for movement in a vertical direction whereas the wands or shafts themselves are slidably received in suitable apertures formed in the said brackets. As already mentioned, the panel 20 may be provided with indicia spaced vertically thereof along the outer edge of each screen 22 and 24 to indicate the relative decibel volume, although such indication need not correspond precisely with a given decibel range since the volume itself is variable. To afford the requisite vertical movement of the flexible shafts 28 and 30in accordance with desired volume changes of bass or treble respectively, the pulley cords or ro es 44 and 46 are mountedon rollers such as roller 48 shown in Fig. 3 which is affixed relative to the manual control knob 18. Thus the roller 48 is secured upon a shaft 50 and is thereby responsive to the control knob 18 which thr ugh the shaft, is adapted to adjust a potentiometer 52 that determines the volume of the treble sound range. The volume indication of the bass range is controlled by a corresponding roller 54 affixed to a potentiometer shaft 56 having the knob 14 secured thereto.

Means are provided for transmitting movement effected by rotation of the respective knobs to the shafts 28 and 30, and such means include a roller wheel 58 preferably disposed substantially above roller 48 and a corresponding roller 60 displaced slightly outwardly relative thereto substantially a radius of roller 58, the rope 46 being mounted over roller 60 so that its inner side is held outwardly by roller 58 substantially vertically. The spacing of roller 48 from roller 58 determines in part the mechanical advantage to be exerted, and it will be seen that where as shown the bass knob 14 is displaced inwardly a considerable distance from a lower roller 62 corresponding to roller 58, so that the amount of movement for the bass may be suitably calibrated with the movement of the shaft 28. A roller 64 maintains the inner side of rope 44 substantially vertical as described with respect to element 46. It will be seen that both sides of the loop thus formed contact roller 62 as a result of the position of knob 14 and its associated roller 54.

Referring again to Fig. l the third or intermediate screen 26 has disposed substantially horizontally thereacross a shaft 66 which rides on a loop 68 controlled by the central panel knob 16 for the volume control. As best seen in Fig. 4, adjustment of the volume control may be made with reference to the position of the shaft 66, which rides by means of a bracket 70 on one side of the loop 68. The loop itself is formed as a frame around the screen 26 by means of four pulley rollers 72, 74, 76 and 78 with the rope being preferably criss-crossed for oriented calibrated control relationship with the control knob 16 which is disposed a predetermined distance below and outwardly of roller 62 as shown for this purpose. Accordingly, shaft 66 may ride vertically in relation to suitable indicia on the side of screen 26 adjacent roller 76 with the desired extent of movement in accordance with spacing of the main control knob from the wheels, it being appreciated again that the amount of adjustment of knob 16 may be greater or less than needed to provide a given amount of movement of shaft 66 to indicate a corresponding displacement within the total volume range represented.

In using the device, a balanced, even emphasis (or flat condition) for bass and treble corresponds to a horizontal straight line formed by shafts 28 and 30. If it is desired to attenuate the bass the left shaft 28 is flexed downwardly by rotation of knob 14 until its outer extremity points to the desired figure, which will substantially correspond to a decibel measure (although, because of the overall line control this is more of a matter of proportion than it is of absolute accuracy, as stated).

Likewise, if it is desired to increase the amount of bass in the given signal the knob is rotated in the opposite direction and again to an extent indicated by suitable indicia or in relationship to the shaft 28 on the treble Where it is desired to make variation equal or in any other way proportionate, so that the shaft will flex upwardly.

Corresponding adjustment is available to determine the relative emphasis of the treble. However, when a tone of absolute flatness or even balance between treble and bass and overall tonal volume, is again desired all that is needed is to visually adjust the rods 28 and 30 until they are once more in straight alignment. The degree of accuracy with which this can be done exceeds anything that is possible with simple adjustment of the manual controls.

Any desired construction of the control rollers may be used, as will be readily appreciated, but the construction shown in Figs. 5 .through 7 is preferred inasmuch as the annular, dished metal bracket 80 affords a certain resiliency which is desirable in a, pulley means as described, this shell being secured at an inner edge 82 of a flat, circular face 84 to a disc 86 on the appropriate shaft, such as shaft 50, by a screw 88. Also, the elevated edge of the bracket may be disposed on a suitable support ring 90. As seen in Fig. 7, however, the bracket may be given a scalloped configuration for further resiliency, and secured as at 92 and 94 to the disc 86.

The circuit with which the present invention or rolloff control may be used is such as may be standard for any preamplifier circuit, but it will be understood that the invention is also useful with any system employing manually rotatable treble and bass control means and although we have herein set forth and described our invention with respect to certain specific principals and details thereof, it will be understood by those skilled in the art that these may be varied without departing from the spirit and scope of the invention as set forth in the hereunto appended claims.

We claim:

1. In a system for use with audio amplifiers and the like having sound, bass and treble level controls linked to indicating means to provide a visual indication of the sound level and the bass and treble sound-strengths in relation to the tonal frequencies thereof, two screens having bass and treble frequency and sound-strength scales respectively calibrated along axes of the screens normal to each other, a flexible wand for each of said paired scales and being oriented along the frequency axes thereof, an anchor bracket for each of said wands for rigidly holding one end of each wand to fixedly relate such ends to coextensive sound-strength positions on the respective scales, a pair of carrier brackets respectively movable along the sound-level axes of said scales at locations adjacent the low frequency end of the bass scale and the high frequency end of the treble scale, said carrier brackets being respectively secured to the other and corresponding ends of said wands so as to afford relative movement between the brackets and wands along the longitudinal axes of the latter, means for moving each carrier bracket in a constrained path along the sound-level axis, a sound strength screen between said two screens having a sound strength scale of the sound level and means for adjusting said sound level control including an indicator movable between said rigidly held ends of the wands.

2. The system of claim 1 in which said first mentioned means, for each of said carrier brackets, comprises a plurality of pulley wheels and an endless cord entrained thereabout, said carrier brackets being respectively secured to said cords.

3. The system of claim 2 in which one of said pulley wheels in the group thereof for each carrier bracket comprises a scalloped roller secured to the level control therefor and having the cord affixed thereto.

4. In a system for use with audio amplifiers and the like having bass, treble and volume level controls to provide a visual indication of the bass and treble soundstrengths in relation to the tonal frequencies thereof and to also provide a visual indication of the volume level, an elongated screen having spaced apart bass and treble frequency scales calibrated along one axis thereof and sound-strength scales calibrated along an axis normal thereto, a volume level scale on the volume level screen calibrated along said last mentioned axis, a flexible wand for each of said bass and treble scales and being oriented along the respective frequency axes thereof, an anchor bracket for each of said wands rigidly supporting one end of each wand in relation to said screen at coextensive sound-strength positions on the bass and treble scales, a pair of carrier brackets respectively located adjacent the low frequency position of said bass scale and high frequency position of said treble scale and being movable along the sound-level axes thereof, said carrier brackets being respectively secured to the other and corresponding ends of said wands so as to atford relative movement between the brackets and wands along the longitudinal axes of the latter, means connecting each said carrier bracket for moving the carrier bracket in a constrained path along the soundlevel axis to flex the wands as the carrier brackets are adjusted, an indicator for said volume level scale between said wands, a mounting bracket secured to said indicator and being movable along the axis of said volume-level scale, and means connecting said mounting bracket and the volume l vel control for moving the mounting bracket in a constrained path along the axis of said volume-level scale as the volume control is adjusted.

5. The system of claim 4 in which said first mentioned means, for each of said carrier brackets, comprises a plurality of pulley wheels and an endless cord entrained thereabout, said carrier brackets being respectively secured to said cords.

6. The system of claim 5 in which one of said pulley wheels in the group thereof for each carrier bracket comprises a scalloped roller secured to the level control therefor and having the cord aflixed thereto.

7. The system of claim 5 in which said last mentioned means comprises a plurality of pulley wheels and an endless cord entrained thereabout, and in which said mounting bracket is aifixed to said last mentioned cord.

8. The system of claim 7 in which one of said pulley wheels in each of the groups thereof respectively associated with the carrier and mounting brackets comprises a roller secured to the level control therefor, said roller for the bass and volume level scales being offset laterally from the path of movement of the carrier bracket and mounting "bracket respectively related to the bass and volume level scales.

References Cited in the file of this patent UNITED STATES PATENTS 2,781,736 Bennett Feb. 19, 1957 FOREIGN PATENTS 760,541 Great Britain Oct. 31, 1956 

